Operating mechanism for type bars of typewriters



G. PREZIOSO OPERATING MECHANISM FOR TYPE BARS OF TYPEWR ITERS Flled Nov 27, 1939 A H rl/l/l/r/l/ll/ March 10, .1942.

Patented Mar. 10, 1942 OPERATING MECHANISM FOR TYPE BARS F TYPEWRITERS Application November 27, 1939, Serial No. 306,423 In Switzerland December 10, 1938 2 Claims.

In all typewriters the type bars normally rest on a support, generally covered with felt or other similar material, so as to avoid noise when the bars fall thereon, after being struck, under the action of return springs.

The desired object, that is to say the elimination of noise, is not always obtained with known devices, as for instance, when a lining material such as soft felt or soft rubber is used, the bar rebounds when it drops, which constitutes a disadvantage when the operator strikes the keys rapidly by reason of the fact that the adjacent bars are liable to hook on one another.

When this disadvantage is sought to be eliminated by using a harder material for the lining, noise is then caused by the shock of the bar when it comes in contact with the lining.

The present invention has for its object an operating device which prevents rebounding of the type bars from their support and eliminates this source of noise by the use of a lining of resilient material which absorbs practically all of the noise of the shock produced by the bar when it drops.

Another object of the present invention is to provide a locking device actuated by the key lever which prevents the rebounding of the type bar when it falls after having been struck.

The figure is a diagrammatic cross sectional view of a typewriter embodying the present improvements.

Referring to the drawing, I represents the platen which serves to support the sheet of paper and with which the type bar comes into contact. 2 indicates the support for the type bars which is provided with a lining of soft resilient material, such as for example rubber, indicated at 23. 3 indicates the type bar carrier portion of the machine on which all the type bars l8 are hinged and which is capable of being moved vertically in a well known manner for case adjustment of said type bars. 4 and 5 are two fixed portions of the framework of the machine.

On the fixed portion 4 of the machine framework are pivoted the key-levers 6, one individual to each of the type-bars I8, while between each key-lever and its related type-bar is a connection which comprises the present invention.

The connection between each key-lever 6 and its related type-bar l8 comprises a substantially horizontally disposed, forwardly and rearwardly extending locking-lever 8 which is pivoted at its forward end, as indicated at 9, to th fixed portion 5 of the machine framework for upward and downward swinging movement; a substantially vertically disposed rocker-lever [3 located rearwardly of the locking-lever 8 and pivoted at its lower end to the fixed portion l of the machine framework for forward and rearward swinging movement; a substantially vertically disposed type-bar actuating lever lfi located rearwardly of the rocker-lever i3 and pivoted at its lower end to the type-bar carrier 3 for forward and rearward swinging movement; a link 1 connecting the key-lever 5 with the locking-lever 8 so that depression of said key-lever swings said lockinglever downwardly; a contractile coil spring l0 connected at its lower end to the locking-lever 8 and suitably anchored at its upper end whereby it tends constantly to swing said locking-lever upwardly; a link 12 joining the rear end of the locking-lever 8 with the upper end of the rockerlever I3 and having pivotal connections I I and M with said locking-lever and said rocker-lever, respectively; a rod 5%; connecting the upper end of the rocker-lever IS with an intermediate portion of the type-bar actuating lever l5; and a link ll connecting the upper end of the lever Hi to the type-bar [8 so that forward swinging movement of said lever ll swings said type-bar to its printing position, shown by dotted lines, from its normal position of rest against the support 23, as shown by full lines.

According to the arrangement illustrated in the drawing, a stop a: limits upward swinging movement of the key-lever 6 and acts through said key-lever and the link connection 1 of the same with the locking-lever 8 to limit upward swinging movement of said locking-lever beyond a position in which said locking-lever is substantially horizontally disposed. However, this arrangement may be reversed by providing a suitable stop to limit upward swinging movement of the locking-lever 8 and to act through said locking-lever and its link connection I with the keylever B to limit upward swinging movement of said key-lever, or, alternatively, separate stops may be provided to limit upward swinging movement of said key-lever and said locking-lever. In any event, the arrangement of thedescribed parts is such that when the key-lever 6 is in its normal or uppermost position and the locking-lever 8 is disposed substantially horizontally, the type-bar I8 is in its normal position of rest against the support or stop 23 and the pivot points 9, H and I4 are disposed in a straight line, thereby positively preventing any upward swinging movement of the type-bar l3 away from its support or stop 23, except by actuation of the key-lever 6.

The rod 15 is of sufficient length so that vertical movements of the type-bar carrier 3 for case adjustment can take place practically without applying any force to the members 8 and I3 or to the type bars and therefore practically without causing the least displacement of the latter, the supporting member 2 for the type bars being secured to the movable type bar carrier 3 and moving therewith.

The operation of this actuating device is as follows.

When a key I9 is depressed in the direction of the arrow 20 the members which it actuates assume the position indicated in broken lines in the drawing, whereby there is produced a movement of the type bar 18 in the direction of the arrow 2| towards the platen I against which it strikes, either for example for small letters by means of the portion a of the bar or for capitals by the portion A when the part 3 carrying the type bars is moved downwardly in the direction of the arrow 22.

When after the typing operation the members return to their position of rest and the type bar which has been actuated falls against its support 2- then, by reason of the provision of the locking lever 8 and the link I2, it cannot rebound in spite of the resiliency of the lining 23 which absorbs the shock as these two members oppose any movement of the lever 13 about its hinge.

From the foregoing it will be seen that the type bar cannot be moved from its position of rest in any way other than by depressing its corresponding key. By reason of the fact that during the return movement of the key into its position of rest, any movement of the other members is prevented and in particular a rebounding of the type bar on its support, it will be seen that this source of noise is consequently eliminated completely. Further as the noise of the shock of the type bar when falling on its support its absorbed completely by the lining 23 no sound is heard when the type bars return to their position of rest.

As will be seen the arrangement as described for the operating members of the type bar ensures a very soft impact by reason of th fact that the members 8 and I2 start from a deadcentre position whilst at the same time there is produced an accelerated movement of the type bar by reason of the movement of the toggle mechanism formed by these two members.

I claim:

1. In a typewriter, a type-bar carrier, a typebar pivoted to said type-bar carrier, said type-bar carrierbeing vertically movable for case adjustment of said type-bar, a pivoted key-lever, said type-bar carrier having a stop member against which said type-bar rests when same is in its normal or atrest position, a substantially vertically disposed rocker-lever pivoted at on end for forward and rearward swinging movement, a connection between said rocker-lever and said type-bar whereby forward swinging movement of the former effects pivotal typing movement of the latter from its normal or at-rest position, said connection comprising a link arranged so that vertical movement of the type-bar carrier for case adjustment is practically ineffective to apply any displacing force to said rocker-lever or to said type-bar, a substantially horizontally disposed locking-lever pivoted at its front end for upward and downward swinging movement, a link connecting the rear end of said locking-lever to the free end of said rocker-lever, a connection between said keylever and said locking-lever whereby depression of said key-lever effects downward swinging movement of said locking-lever and forward swinging movement of said rocker-lever and consequent pivotal typing movement of said typebar from its normal or at-rest position, yieldable means tending constantly to move said lockinglever upwardly, and means limiting upward movement of said locking-lever to a position in which same and said link are longitudinally alined when the type-bar is in its normal or atrest position, whereby the type-bar is prevented from being moved from its normal or at-rest position except by depression of said key-lever.

2. In a typewriter, a fixed support, a type-bar carrier, a type-bar pivoted to said type-bar carrier, said type-bar carrier being vertically movable for case adjustment of said type-bar, a keylever pivoted to said fixed support, said type-bar carrier including a stop member against which said type-bar rests when same is in its normal or at-rest position, a substantially vertically disposed rocker-lever pivoted at its lower end to said fixed support for forward and rearward swinging movement, a connection between said rocker-lever and said type-bar whereby forward swinging movement of said rocker-lever effects pivotal typing movement of said type-bar from its normal or at-rest position, said connection comprising a link arranged so that vertical movement of the type-bar carrier for case adjustment is practically ineffective to apply any displacing force to said rocker-lever or to said type-bar, a second fixed support, a substantially horizontally disposed locking-lever pivoted at its forward end to said second fixed support for upward and downward swinging movement, a link connecting the rear end of said locking-lever to the upper end of said rocker-lever, a connection between said key-lever and said locking-lever whereby depression of said key-lever effects downward swinging movement of said lockinglever and forward swinging movement of said rocker-lever and consequent pivotal typing movement of said type-bar from its normal or at-rest position, yieldable means tending constantly to move said locking-lever upwardly, and stop means limiting upward movement of said locking-lever to a position in which same and said link are longitudinally alined when the type-bar is in its normal or at-rest position, whereby the type-bar is prevented from being moved from its normal or at-rest position except by depression of said key-lever.

GIUSEPPE PREZIOSO. 

